Which statement accurately describes Thevenin and Norton equivalents?

• A. Thevenin uses capacitor with resistor; Norton uses a passive network
• B. Both require the same type of source
• C. Thevenin uses current source in parallel; Norton uses a voltage source in series
• D. Thevenin uses voltage source in series with a resistor; Norton uses a current source in parallel with a resistor

Answer: (D)

The essential idea is that any linear, bilateral network can be represented from its terminals in two equivalent ways: a Thevenin model and a Norton model. The Thevenin form is a voltage source in series with a resistor. The Norton form is a current source in parallel with a resistor. They behave identically for any load connected to the same two terminals.

This is why the statement about Thevenin and Norton is the best: it captures the standard definitions and their direct relationship. The resistance is the same in both representations, and the sources are related by I_N = V_th / R_th. You can convert between them by turning the voltage source and series resistor into a current source and parallel resistor, and vice versa.

Why the other ideas don’t fit: Thevenin and Norton aren’t defined by a capacitor with a resistor, and they aren’t restricted to one type of source. Thevenin uses a voltage source in series with a resistor, while Norton uses a current source in parallel with a resistor—the two forms are duals of each other.